The present invention relates to a light mould component for filling concrete. It includes a mould body, and it is characterized by that on at least one side surface of said mould body at least one recessed groove which is passed through upper and lower surfaces is set, at least one vertical turning corner position of same side surface has a vertical curved angle passed through upper and lower surfaces, and the transverse turning corner position of lower side of same side surface has a transverse internal corner which is perpendicularly-crossed or obliquely-crossed with the vertical curved angle or recessed groove; two mould bodies are spaced and arranged, and connected together by means of bottom surface or/and connecting component. Said invention can be used for in-situ casting reinforced concrete or prestressed reinforced concrete hollow floor, roof, wall body, foundation bedplate and open-web bridge. Specially, it can be used for in-situ casting hollow beamless floor. |